package org.afei.ioc.util;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang.StringUtils;

import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * 反射工具类，对java反射的二次封装
 *
 * @author afei
 * @date 17-5-25.
 */
public final class ReflectionUtil {

    private ReflectionUtil() {
    }

    public static Object getInstance(String type) {
        Object o = null;
        try {
            o = Class.forName(type).newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return o;
    }

    public static <T> T getInstance(Class<T> clazz) {
        T o = null;
        try {
            o = clazz.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return o;
    }

    public static Field[] getFields(Object obj) {
        Field[] fields = obj.getClass().getDeclaredFields();

        return fields;
    }

    public static Method[] getMethods(Object obj) {
        Method[] methods = obj.getClass().getDeclaredMethods();
        return methods;
    }

    public static Method getMethod(Object obj, String methodName) {
        Method[] methods = obj.getClass().getDeclaredMethods();
        Method result = null;
        for (int i = 0; i < methods.length; i++) {
            if (methodName.equals(methods[i].getName())) {
                result = methods[i];
                break;
            }
        }

        return result;
    }

    /**
     * 执行某个方法
     *
     * @param obj
     * @param method
     * @param args
     * @return
     */
    public static Object invoke(Object obj, Method method, Object... args) {
        Object result = null;

        try {
            result = method.invoke(obj, args);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        return result;
    }

    /**
     * 读取对象属性值,支持嵌套属性如 user.department.name
     */
    public static Object getProperty(Object obj, String propertyName) {
        if (propertyName == null || propertyName.length() < 1) {
            return obj;
        }
        int pos = propertyName.indexOf(".");
        if (pos < 0) {
            return getFieldValue(obj, propertyName);
        }
        String baseProperty = propertyName.substring(0, pos);
        String childProperty = propertyName.substring(pos + 1);
        Object target = getFieldValue(obj, baseProperty);
        return getProperty(target, childProperty);
    }

    /**
     * 直接读取对象属性值,无视private/protected修饰符,不经过getter函数.
     */
    public static Object getFieldValue(final Object object, final String fieldName) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        Object result = null;
        try {
            result = field.get(object);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * 直接设置对象属性值,无视private/protected修饰符,不经过setter函数.
     */
    public static void setFieldValue(final Object object, final String fieldName, final Object value) {
        Field field = getDeclaredField(object, fieldName);

        if (field == null)
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

        makeAccessible(field);

        try {
            field.set(object, value);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * 循环向上转型,获取对象的DeclaredField.
     */
    protected static Field getDeclaredField(final Object object, final String fieldName) {
        return getDeclaredField(object.getClass(), fieldName);
    }

    /**
     * 循环向上转型,获取类的DeclaredField.
     */
    @SuppressWarnings("unchecked")
    protected static Field getDeclaredField(final Class clazz, final String fieldName) {
        for (Class superClass = clazz; superClass != Object.class; superClass = superClass.getSuperclass()) {
            try {
                return superClass.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

    /**
     * 强制转换fileld可访问.
     */
    protected static void makeAccessible(final Field field) {
        if (!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
            field.setAccessible(true);
        }
    }

    /**
     * 通过反射,获得定义Class时声明的父类的泛型参数的类型. 如public UserDao extends HibernateDao<User>
     *
     * @param clazz The class to introspect
     * @return the first generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings("unchecked")
    public static Class getSuperClassGenricType(final Class clazz) {
        return getSuperClassGenricType(clazz, 0);
    }

    /**
     * 通过反射,获得定义Class时声明的父类的泛型参数的类型. 如public UserDao extends HibernateDao<User,Long>
     *
     * @param clazz clazz The class to introspect
     * @param index the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be determined
     */

    @SuppressWarnings("unchecked")
    public static Class getSuperClassGenricType(final Class clazz, final int index) {

        Type genType = clazz.getGenericSuperclass();

        if (!(genType instanceof ParameterizedType)) {
            // logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0) {
            // logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
            //         + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            //logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
            return Object.class;
        }
        return (Class) params[index];
    }

    /**
     * 提取集合中的对象的属性,组合成List.
     *
     * @param collection   来源集合.
     * @param propertyName 要提取的属性名.
     */
    @SuppressWarnings("unchecked")
    public static List fetchElementPropertyToList(final Collection collection, final String propertyName)
            throws Exception {

        List list = new ArrayList();

        for (Object obj : collection) {
            list.add(PropertyUtils.getProperty(obj, propertyName));
        }

        return list;
    }

    /**
     * 提取集合中的对象的属性,组合成由分割符分隔的字符串.
     *
     * @param collection   来源集合.
     * @param propertyName 要提取的属性名.
     * @param separator    分隔符.
     */
    @SuppressWarnings("unchecked")
    public static String fetchElementPropertyToString(final Collection collection, final String propertyName,
                                                      final String separator) throws Exception {
        List list = fetchElementPropertyToList(collection, propertyName);
        return StringUtils.join(list, separator);
    }

    /**
     * 将list的数据通过分割符组成字符串
     *
     * @param valueList
     * @param separator
     * @return
     * @author huwanshan
     * @date 2010-12-11 下午07:50:35
     */
    @SuppressWarnings("unchecked")
    public static String toReadableString(List valueList, String separator) {
        return StringUtils.join(valueList, separator);
    }

}
